This invention relates to urethane coatings, and more particularly to an improved high solids urethane coating composition.
Urethane coatings are useful in automotive and appliance applications. It is of advantage to provide such coating compositions with high solids content of, for example, 70% volume solids or greater. High solids coatings permit thinner wet films which have the same dry film thickness (solids) as conventional low solids formulations, and cure at low baking temperatures; however, low viscosity, low volatility, and controlled reactivity of high solids urethane coatings make their formulation difficult. Heretofore, high solids urethanes generally have been formulated from polyiscyanates reacted with polyols, but these polyurethanes invariably lack low viscosity and high molecular weight.
The present invention overcomes such prior problems by providing a high solids coating composition of low viscosity and higher molecular weight which cures to form an unusually good, tack-free, tough, flexible urethane film.